Technical practice
How would you turn a customer-facing feature request into a backend design and release plan?
What to coverSuggested answer focus: Clarify user value and requirements, then describe API and data design, testing, deployment, and iteration. Explain how you would make trade-offs between delivery speed, reliability, and future changes.
How would you design a REST API for a product feature that needs to evolve?
What to coverSuggested answer focus: Discuss resource boundaries, request validation, error responses, and compatibility for existing clients. Explain how you would keep the implementation maintainable and testable in Java with Spring Boot or Python.
How would you design microservices to remain reliable under high load?
What to coverSuggested answer focus: Explain service boundaries, communication, failure handling, and how you would identify capacity limits. Compare the benefits of separating services with the operational complexity that separation introduces.
How would you investigate a production performance issue in a backend service?
What to coverSuggested answer focus: Describe how you would narrow down the affected requests and bottleneck, form a hypothesis, and verify a fix. Address how to protect users while diagnosing the issue and how to check whether performance improved.
How would you choose and design database storage for a new product feature?
What to coverSuggested answer focus: Compare a relational option such as PostgreSQL or MySQL with MongoDB based on the feature’s data and access patterns. Discuss queries, data consistency, and how the design would hold up as usage grows.
What data-structure or algorithm choices could matter in a high-traffic backend workflow?
What to coverSuggested answer focus: Use a concrete hypothetical workflow to compare time and memory costs, including what changes as input size or request volume grows. Explain how you would confirm that an optimization addresses a real bottleneck.
How would you use a cloud platform when deploying and operating a backend service?
What to coverSuggested answer focus: Use AWS, Google Cloud, or Azure as an example and discuss deployment, scaling, and observing service health. Keep the answer grounded in platform concepts you know rather than assuming this role uses a particular service.
How would you integrate an LLM API into a customer-facing backend workflow?
What to coverSuggested answer focus for this good-to-have area: Describe where the API call belongs, how its output reaches the application, and how you would validate it. Discuss retries and fallbacks when the provider fails or returns an unusable response.
How would you prepare structured or unstructured data for an AI-enabled product feature?
What to coverSuggested answer focus for this good-to-have area: Describe a data flow that makes relevant inputs available to an AI feature such as summarization or recommendations. Explain how you would check input quality and whether the resulting output is useful to the user.
How would you decide whether an AI capability adds value to an existing product workflow?
What to coverSuggested answer focus for this good-to-have area: Compare an AI-enabled approach with a simpler alternative using the user need, output quality, latency, and failure handling. Explain what you would measure before expanding the feature.
Behavioural practice
Tell me about a feature you owned from requirements through deployment and iteration.
What to coverSuggested answer focus: Give the situation and user need, the design and delivery actions you took, and the result after release. Be specific about your own decisions and what feedback changed in a later iteration.
Describe a time you worked with product, design, or QA to resolve a delivery trade-off.
What to coverSuggested answer focus: Set out the competing priorities, how you worked with others to decide, and the resulting product or delivery outcome. Distinguish your contribution from the team’s shared work.
Tell me about a production issue you helped resolve.
What to coverSuggested answer focus: Explain the impact and your role, the steps you took to diagnose and address the issue, and the result. Include what the team changed afterward to reduce recurrence, if applicable.
Describe an architecture decision where you balanced an immediate feature need with longer-term maintainability.
What to coverSuggested answer focus: State the situation and options, your reasoning and actions, and the outcome for users or the system. Acknowledge a trade-off or uncertainty rather than presenting the decision as cost-free.